I'm sorry to hear your stuck! Let''s learn how to do this.
Simplify both sides of the equation!
−25(10−x)=5x+50
(−25)(10)+(−25)(−x)=5x+50 - Distribute
−250+25x=5x+50
25x−250=5x+50
Now subtract 5x to each side.
25x−250−5x=5x+50−5x
20x−250=50
Add 250 to both sides. (We need to get x by itself)
20x−250+250=50+250
20x=300
Divide both sides by 20!
You get x = 15.
I'd take notes and look through on how this problem was solved for future references.
Have a good one!